In the state of the art, the PVC profiled elements, mainly used as window and door frames, are welded together by means of the melting of respective head surfaces in order to make a frame structure fittable to doors or windows.
In particular, the melting is done by heating the portions to be connected using suitable electric heating plates and then pressing the heated portions the one against the other to favor melting.
Generally, the heated portions are the head extremities of the profiled elements, suitably cut at 45° to define e.g. a right-angled portion of a respective window or door frame.
This method is carried out by welding machines equipped with respective retaining members of the profiled elements, mobile in a reciprocal closer moving direction to bring the heated extremities to be welded into contact.
Such machines are also equipped with finishing systems, suitable for removing the bead or welding bead which forms during the melting of the two profiled elements.
In fact, in correspondence to the joining line of the two profiled elements (surfaces cut at 45°), the portion of melted material in excess comes out and goes to form a bead protruding from the visible surface of the profiled elements. For this reason, in order to give the finished door or window frame an appreciable aesthetic appearance, once welded the profiled elements undergo a bead removal operation.
The known welding devices briefly described do however have major drawbacks mainly tied to the formation of the above-mentioned welding bead.
It must in fact be considered that the welding zone of the PVC profiled elements is not perfectly uniform and consequently, to make the profiled elements even, a lot of material is melted with the consequent formation of an abundant bead, and there is consequently a lot of waste material to be removed.
Furthermore, the finishing jobs for removing the bead and cleaning the welding zone have a strong effect on the total time required to machine the door or window frame. It should be realized in fact that for every door or window frame welding operation, the profiled elements have to be subsequently machined. Furthermore, in the case of spoked profiled elements, the removal of said bead is very complicated.
Furthermore, the machinery used for the above-mentioned finishing operations is cumbersome and particularly expensive.
This results in the need to sustain additional costs and work times because of the presence of further cumbersome equipment and tools.